The invention relates generally to the field of air routing systems. In particular, this invention relates to a multi-purpose air cycle system for use in a vehicle having an internal combustion engine.
Present day automobile air conditioning systems commonly use refrigerants such as freon or R134a. A standard refrigerant loop includes a compressor, an evaporator, a condenser, a receiver, a drier, an expansion valve and numerous refrigerant hoses. These standard configurations have disadvantages, however. For example, the refrigerant level must be monitored and refilled during the life of the vehicle. Furthermore, emissions from materials such as freon can also cause environmental problems.
Standard refrigerant loops require a large amount of package space in the vehicle, requiring other components of the vehicle to be reduced in size in order to accommodate the air conditioning system. Additionally, standard automobile air conditioning systems are only utilized to regulate the climate of the vehicle, while other systems are necessary to cool and/or supercharge the engine. This also requires increased package size and increases the weight of the vehicle.
Many prior art systems utilizing an open Brayton refrigeration cycle have an isentropic efficiency that is below acceptable levels for automobile air conditioning systems. In addition, prior art systems integrating supercharging with climate control have had difficulty adequately regulating the temperature of the air supplied to the interior of the vehicle. It is desirable to integrate the air conditioning system with the engine supercharging and cooling systems to reduce package size and weight, while also maintaining adequate and efficient control over the temperature and humidity of the conditioned air supplied to the interior of the vehicle.
In one embodiment of the present invention, an air cycle system for use in a vehicle having an internal combustion engine is provided. A compressor has an outflow to an intercooler with an outflow to a first bypass valve. The first bypass valve has an open and a closed orientation, directing air to the engine of the vehicle in the open orientation and directing air to an expander in the closed orientation. The expander has an outflow to a second bypass valve that is adjustable so it can direct a variable fraction of air to the engine and the remainder of the air to an air handling unit. The air handling unit has at least a fan, a scroll center, and first and second air flow paths. The first air flow path has an input at the scroll center from the second bypass valve and the second air flow path has an input at the fan from the interior of the vehicle. The air handling unit mixes air from the first and second flow paths and directs the mixed air to the interior of the vehicle.
In a second embodiment of the present invention, an air cycle system for use in a vehicle having an internal combustion engine is provided. A compressor has an output to an intercooler having an outlet to a first bypass valve. The first bypass valve has an open orientation wherein cooled and pressurized air is supplied to the engine and a closed orientation wherein air is directed to an expander. The expander has an output to a second bypass valve capable of supplying a variable amount of cooled and dried air to the engine and the remaining air to an air mixing device at a first input. The air mixing device has a second input from the interior of the vehicle and is capable of mixing air from the second bypass valve and the second input and directing the mixed air to the interior of the vehicle.
In a third embodiment of the present invention, a method for supplying conditioned air to the interior of a vehicle, pressurized air to an engine for aid during acceleration, and cooling air to an engine to improve horsepower and fuel economy is provided. The method comprises the steps of first increasing air pressure in a compressor and cooling the air in an intercooler. This air is routed from the intercooler to the engine during high demand conditions and routed to an expander during low demand conditions. The air routed to the expander is cooled in the expander and a variable fraction of this cooled air is routed to the engine to cool the engine. The remainder of this air is routed to an air mixing device where the air is mixed with air from the interior of the vehicle. This mixed air is delivered to the interior of the vehicle for climate control.